The focal mechanisms of 32 earthquakes with magnitude of M_S≥3.0, which were recorded by the Guangdong Digital Seismographic Network, are calculated by using P-wave polarity and amplitude ratio data, and those of 83 ...The focal mechanisms of 32 earthquakes with magnitude of M_S≥3.0, which were recorded by the Guangdong Digital Seismographic Network, are calculated by using P-wave polarity and amplitude ratio data, and those of 83 earthquakes of Guangdong and its adjacent areas derived by previous researchers are sorted out. On the basis of this, the characteristics of focal mechanism in Guangdong and its adjacent areas are summarized. Meanwhile the focal mechanisms of three earthquake areas, i.e., Yangjiang, Xinfengjiang and Nanao, are discussed respectively. Results show clear regional feature in the function and nature of the stress, and earthquakes are mostly of strike-slip associated with dip-slip component. Earthquakes in the Xinfengjiang Reservoir area are all reservoir-induced ones, so they are only of strike-slip and normal faulting types. In the Yangjiang area, some thrust earthquakes occurred. The dominant orientation of principal compressive stress axis changes from NS in Hainan, Gaungxi to NWW in Guangdong and finally near EW in the coastal areas of Guangdong and Fujian Provinces.展开更多
文摘The focal mechanisms of 32 earthquakes with magnitude of M_S≥3.0, which were recorded by the Guangdong Digital Seismographic Network, are calculated by using P-wave polarity and amplitude ratio data, and those of 83 earthquakes of Guangdong and its adjacent areas derived by previous researchers are sorted out. On the basis of this, the characteristics of focal mechanism in Guangdong and its adjacent areas are summarized. Meanwhile the focal mechanisms of three earthquake areas, i.e., Yangjiang, Xinfengjiang and Nanao, are discussed respectively. Results show clear regional feature in the function and nature of the stress, and earthquakes are mostly of strike-slip associated with dip-slip component. Earthquakes in the Xinfengjiang Reservoir area are all reservoir-induced ones, so they are only of strike-slip and normal faulting types. In the Yangjiang area, some thrust earthquakes occurred. The dominant orientation of principal compressive stress axis changes from NS in Hainan, Gaungxi to NWW in Guangdong and finally near EW in the coastal areas of Guangdong and Fujian Provinces.
